| 1. |
- Beal, Jacob, et al.
(författare)
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Robust estimation of bacterial cell count from optical density
- 2020
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Ingår i: Communications Biology. - : Springer Science and Business Media LLC. - 2399-3642. ; 3:1
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Tidskriftsartikel (refereegranskat)abstract
- Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data.
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| 2. |
- Arndt, D. S., et al.
(författare)
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STATE OF THE CLIMATE IN 2017
- 2018
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Ingår i: Bulletin of The American Meteorological Society - (BAMS). - : American Meteorological Society. - 0003-0007 .- 1520-0477. ; 99:8, s. S1-S310
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Forskningsöversikt (refereegranskat)
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| 3. |
- Espinosa, Lisa, et al.
(författare)
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Pavlovian threat conditioning can generate intrusive memories that persist over time
- 2022
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Ingår i: Behaviour Research and Therapy. - : Elsevier. - 0005-7967 .- 1873-622X. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Although Pavlovian threat conditioning has proven to be a useful translational model for the development of anxiety disorders, it remains unknown if this procedure can generate intrusive memories - a symptom of many anxiety-related disorders, and whether intrusions persist over time. Social support has been related to better adjustment after trauma however, experimental evidence regarding its effect on the development of anxietyrelated symptoms is sparse. We had two aims: to test whether threat conditioning generates intrusive memories, and whether different social support interactions impacted expression of emotional memories. Non-clinical participants (n = 81) underwent threat conditioning to neutral stimuli. Participants were then assigned to a supportive, unsupportive, or no social interaction group, and asked to report intrusive memories for seven days. As predicted, threat conditioning can generate intrusions, with greater number of intrusions of CS+ (M = 2.35, SD = 3.09) than CS- (M = 1.39, SD = 2.17). Contrary to predictions, compared to no social interaction, supportive social interaction did not reduce, and unsupportive interaction did not increase skin conductance of learned threat or number of intrusions. Unsupportive interaction resulted in a relative difference in number of intrusions to CS + vs CS-, suggesting that unsupportive interaction might have increased image-based threat memories. Intrusions were still measurable one year after conditioning (one-year follow-up; n = 54), when individuals with higher trait anxiety and greater number of previous trauma experiences reported more intrusions. Our findings show that threat conditioning can create long-lasting intrusions, offering a novel experimental psychopathology model of intrusive memories with implications for both research on learning and clinical applications.
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| 4. |
- Karikari, Thomas, et al.
(författare)
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An extensive plasmid library to prepare tau protein variants and study their functional biochemistry.
- 2020
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Ingår i: ACS chemical neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 11:19
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Tidskriftsartikel (refereegranskat)abstract
- Tau neurofibrillary tangles are key pathological features of Alzheimer's disease and other tauopathies. Recombinant protein technology is vital for studying the structure and function of tau in physiology and aggregation in pathophysiology. However, open-source and well-characterized plasmids for efficiently expressing and purifying different tau variants are lacking. We generated 44 sequence-verified plasmids including those encoding full length (FL) tau-441, its four-repeat microtubule-binding (K18) fragment, and their respective selected familial pathological variants (N279K, V337M, P301L, C291R and S356T). Moreover, plasmids for expressing single (C291A), double (C291A/C322A) and triple (C291A/C322A/I260C) cysteine-modified variants were generated to study alterations in cysteine content and locations. Furthermore, protocols for producing representative tau forms were developed. We produced and characterized the aggregation behavior of the triple cysteine-modified tau-K18, often used in real-time cell internalization and aggregation studies because it can be fluorescently labeled on a cysteine outside the microtubule-binding core. Similar to the wild type (WT), triple cysteine-modified tau-K18 aggregated by progressive -sheet enrichment, albeit at a slower rate. On prolonged incubation, cysteine-modified K18 formed paired helical filaments similar to those in Alzheimer's disease, sharing morphological phenotypes with WT tau-K18 filaments. Nonetheless, cysteine-modified tau-K18 filaments were significantly shorter (p=0.002) and mostly wider than WT filaments, explainable by their different principal filament elongation pathways: vertical (end-to-end) and lateral growth for WT and cysteine-modified respectively. Cysteine rearrangement may therefore induce filament polymorphism. Together, the plasmid library, the protein production methods, and the new insights into cysteine-dependent aggregation, should facilitate further studies and the design of anti-aggregation agents.
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| 5. |
- Krans, Julie, et al.
(författare)
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"I see what you're saying" : Intrusive images from listening to a traumatic verbal report
- 2010
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Ingår i: Journal of Anxiety Disorders. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0887-6185 .- 1873-7897. ; 24:1, s. 134-140
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Tidskriftsartikel (refereegranskat)abstract
- We tested the hypothesis that intrusive visual images could develop from listening to a traumatic verbal report. Eighty-six participants listened to a traumatic verbal report under one of three conditions: while shaping plasticine (visuospatial condition), while performing articulatory suppression (verbal condition), or with no extra task (control condition). Results showed that intrusive visual images developed from listening to the traumatic report. In line with the idea that central executive processes guide encoding of information, intrusion frequency was reduced in both the visuospatial and the verbal condition compared to the no task control condition. Overall. this pattern is similar to intrusive images from a traumatic film as found in earlier studies. This study provides a valuable addition to models of posttraumatic stress disorder and autobiographical memory. Additionally, the results have potential implications for therapists working with traumatized individuals. (C) 2009 Elsevier Ltd. All rights reserved.
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| 6. |
- Krans, Julie, et al.
(författare)
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Intrusive Trauma Memory : A Review and Functional Analysis
- 2009
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Ingår i: Applied Cognitive Psychology. - : WILEY-BLACKWELL. - 0888-4080 .- 1099-0720. ; 23:8, s. 1076-1088
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Forskningsöversikt (refereegranskat)abstract
- Our contribution to this special issue focuses on the phenomenon of intrusive trauma memory. While intrusive trauma memories can undoubtedly cause impairment. we argue that they may exist for a potentially adaptive reason. Theory and experimental research on intrusion development are reviewed and possible functions of intrusive trauma memory are explored. These functions include aiding emotional processing, preventing future harm and protecting the coherence of the self. The issue of intrusive images in other disorders than posttraumatic stress disorder is briefly addressed. This review suggests that the study of function is important for a nuanced view on the modulation of intrusive trauma memory in both experimental psychopathology and clinical treatment. Copyright (C) 2009 John Wiley & Sons, Ltd.
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| 7. |
- Krans, Julie, et al.
(författare)
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Motion Effects on Intrusion Development
- 2010
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Ingår i: Journal of Trauma & Dissociation. - : ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD. - 1529-9732 .- 1529-9740. ; 11:1, s. 73-82
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Tidskriftsartikel (refereegranskat)abstract
- Analogue studies on intrusion development have found that visuospatial tasks performed during the encoding of aversive information reduce subsequent intrusion development. However, these studies cannot rule out a physical explanation in terms of simple movement. In the current study we addressed this issue. Healthy participants viewed an aversive film while performing a visuospatial movement task, a configurational movement task, or no task. Intrusive images from the film were reported in a diary during the week following film viewing. In line with an information-processing account of posttraumatic stress disorder, intrusion frequency was significantly reduced by the visuospatial movement task but not the configurational movement task compared to no task. This finding supports the role of visuospatial processing specifically in intrusion development.
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| 8. |
- Krans, Julie, et al.
(författare)
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Tell me more : Can a memory test reduce analogue traumatic intrusions?
- 2009
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Ingår i: Behaviour Research and Therapy. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0005-7967 .- 1873-622X. ; 47:5, s. 426-430
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Tidskriftsartikel (refereegranskat)abstract
- Information processing theories of post-traumatic stress disorder (PTSD) state that intrusive images emerge due to a lack of integration of perceptual trauma representations in autobiographical memory. To test this hypothesis experimentally, participants were shown an aversive film to elicit intrusive images. After viewing, they received a recognition test for just one part of the film. The test contained neutrally formulated items to rehearse information from the film. Participants reported intrusive images for the film in an intrusion diary during one week after viewing. In line with expectations, the number of intrusive images decreased only for the part of the film for which the recognition test was given. Furthermore, deliberate cued-recall memory after one week was selectively enhanced for the film part that was in the recognition test a week before. The findings provide new evidence supporting information processing models of PTSD and have potential implications for early interventions after trauma. (C) 2009 Elsevier Ltd. All rights reserved.
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| 9. |
- Lakens, Daniel, et al.
(författare)
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Justify your alpha
- 2018
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Ingår i: Nature Human Behaviour. - : Nature Publishing Group. - 2397-3374. ; 2:3, s. 168-171
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Tidskriftsartikel (refereegranskat)abstract
- In response to recommendations to redefine statistical significance to P ≤ 0.005, we propose that researchers should transparently report and justify all choices they make when designing a study, including the alpha level.
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| 10. |
- Lundgren, Markus, et al.
(författare)
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Analgesic antipyretic use among young children in the TEDDY study : No association with islet autoimmunity
- 2017
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Ingår i: BMC Pediatrics. - : Springer Science and Business Media LLC. - 1471-2431. ; 17:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: The use of analgesic antipyretics (ANAP) in children have long been a matter of controversy. Data on their practical use on an individual level has, however, been scarce. There are indications of possible effects on glucose homeostasis and immune function related to the use of ANAP. The aim of this study was to analyze patterns of analgesic antipyretic use across the clinical centers of The Environmental Determinants of Diabetes in the Young (TEDDY) prospective cohort study and test if ANAP use was a risk factor for islet autoimmunity. Methods: Data were collected for 8542 children in the first 2.5 years of life. Incidence was analyzed using logistic regression with country and first child status as independent variables. Holm's procedure was used to adjust for multiplicity of intercountry comparisons. Time to autoantibody seroconversion was analyzed using a Cox proportional hazards model with cumulative analgesic use as primary time dependent covariate of interest. For each categorization, a generalized estimating equation (GEE) approach was used. Results: Higher prevalence of ANAP use was found in the U.S. (95.7%) and Sweden (94.8%) compared to Finland (78.1%) and Germany (80.2%). First-born children were more commonly given acetaminophen (OR 1.26; 95% CI 1.07, 1.49; p = 0.007) but less commonly Non-Steroidal Anti-inflammatory Drugs (NSAID) (OR 0.86; 95% CI 0.78, 0.95; p = 0.002). Acetaminophen and NSAID use in the absence of fever and infection was more prevalent in the U.S. (40.4%; 26.3% of doses) compared to Sweden, Finland and Germany (p < 0.001). Acetaminophen or NSAID use before age 2.5 years did not predict development of islet autoimmunity by age 6 years (HR 1.02, 95% CI 0.99-1.09; p = 0.27). In a sub-analysis, acetaminophen use in children with fever weakly predicted development of islet autoimmunity by age 3 years (HR 1.05; 95% CI 1.01-1.09; p = 0.024). Conclusions: ANAP use in young children is not a risk factor for seroconversion by age 6 years. Use of ANAP is widespread in young children, and significantly higher in the U.S. compared to other study sites, where use is common also in absence of fever and infection.
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